If you want the genuinely green option, Earthborn is the one I point people to first. It's clay and mineral based, near-zero VOC, free of acrylics and oils, and it carries the EU Ecolabel — one of the few paints in the UK that actually does. Their Claypaint is properly breathable, which makes it brilliant for old houses with lime plaster or any wall that needs to let moisture out. It's a lovely chalky finish too, not just a worthy one.
Next is Edward Bulmer Natural Paint. This is about as honest as eco gets — plant and mineral based, plastic-free binders, no petrochemicals, and the company is transparent about every ingredient. The colours are gorgeous, historically informed and deeply pigmented. It's a premium price, but you're paying for the real thing rather than greenwash.
Among the bigger names, Little Greene deserves credit. Their water-based range is near-zero VOC, the tins are recyclable, and they're a B Corp. COAT is another genuinely good shout — water-based, low VOC, B Corp certified, and they run a recycling scheme for empty tins. Both give you a modern, durable finish without the heavy solvent load.
Now the "but what about": don't confuse "low VOC" with "natural." Almost every mainstream brand — Dulux, Crown, Farrow & Ball — has cut VOCs hard over the last decade, and a modern water-based emulsion is far cleaner than the oil paints of twenty years ago. But low VOC still usually means acrylic (plastic) binders. Earthborn and Edward Bulmer are the ones doing something fundamentally different.
Practical advice: match the paint to the wall. For breathable old plaster or damp-prone rooms, Earthborn Claypaint earns its keep. For a durable, washable family-home finish with a clear conscience, COAT or Little Greene. And whatever you buy, don't pour leftovers down the drain — take them to a Community RePaint scheme. That's the most eco thing you can do with paint, full stop.